Rudolf Höss returns to Auschwitz to take command of the extermination camp again.
Höss had previously been in charge of all Auschwitz camps, but in December 1943 he was replaced by Arthur Liebehenschel who only commanded Auschwitz I and who was far more lenient than Höss.
Now, however, Rudolf Höss returns and is given authority over all the Auschwitz camps again. He's brought back in part because he's needed to supervise the extermination of the Hungarian Jews who began being transported to Auschwitz a few days ago and who will be arriving at a rate of several thousand a day over the next few months.
Almost all of the gassing of Hungarian Jews occurs after Höss assumes command again at Auschwitz. The first thing he does as commandant is order the construction of a branch rail line that will take the trains of Jews into Auschwitz-Birkenau within a few yards of the main crematoria.
Höss writes about the extermination of the Hungarian Jews:
"On Pohl's orders I made three visits to Budapest in order to obtain an estimate of the number of able-bodied Jews that might be expected. [...]
Eichmann was completely obsessed with his mission and also convinced that this extermination action was necessary in order to preserve the German people in the future from the destructive intentions of the Jews.
Eichmann was also a determined opponent of the idea of selecting from the transports Jews who were fit for work. He regarded it as a constant danger to his scheme for a"final solution'' because of the possibility of mass escapes or some other event occurring which would enable the Jews to survive."